System to provide high speed, high accuracy motion

A device for supporting and moving an item, comprising:

• carriage means for holding the item;
• actuator means for applying a force to move the carriage means;
• flexural coupling means for transmitting the force from the actuator means to the carriage means;
• carriage sensing means for measuring the position of the carriage means;
• actuator sensing means for measuring the position of the actuator means;
• and
• control means for receiving data from the carriage sensing means and the actuator sensing means and for controlling the actuator means such that the carriage is moved quickly and accurately to a desired position
• wherein the actuator means and the carriage means have desired positions corresponding to the desired position of the item, and wherein the control means controls the actuator means by generating signals, referred to as control force commands, indicating how much force is to be applied by the actuator means, the signal corresponding to the largest force that the actuator means is capable of applying being called a maximum force command, and calculate each control force command by repeating the following steps using variables x1, x2, x1desired, x2desired, u1, u1old1, u1old2, u2, u2old1, u2old2, e1, e1old1, e1old2, e2, e2old1, e2old2, a11, a12, a13, a14, a15, a21, a22, a23, a24 and a25, in a series of iterations, including a first iteration and subsequent iterations, each subsequent iteration having a previous iteration, until the carriage means and the actuator means reach their desired positions:
• (a) determining e1 by subtracting x1, which represents the current position of the carriage means, from x1desired, which represents the desired position of the carriage means;
• (b) determining e2 by subtracting x2, which represents the current position of the actuator means, from x2desired, which represents the desired position of the actuator means;
• (c) determining u1 by finding the sum of the products:
• (a11*e1), (a12*e1old1), (a13*e1old2), (a14*u1old1), and (a15*u1old2), wherein a11, a12, a13, a14 and a15 are coefficients for a recursive digital control algorithm, and wherein e1old2 equals zero for the first iteration and e1old1 of the previous iteration for subsequent iterations, e1old1 equals zero for the first iteration and e1 of the previous iteration for subsequent iterations, u1old2 equals zero for the first iteration and u1old1 of the previous iteration for subsequent iterations, and u1old1 equals zero for the first iteration and u1 of the previous iteration for subsequent iterations;
• (d) reducing u1 to one-half of the maximum force command if the u1 calculated in step (c) is greater than one-half of the maximum force command;
• (e) determining u2 by finding the sum of the products:
• (a21*e2), (a22*e2old1), (a23*e2old2) (a24*u2old1), and a (25*u2old2), wherein a21, a22, a23, a24 and a25 are coefficients for a recursive digital control algorithm, and wherein e2old2 equals zero for the first iteration and e2old1 of the previous iteration for subsequent iterations, e2old1 equals zero for the first iteration and e2 of the previous iteration for subsequent iterations, u2old2 equals zero for the first iteration and u2old1 of the previous iteration for subsequent iterations, and u2old1 equals zero for the first iteration and u2 of the previous iteration for subsequent iteration;
• (f) reducing u2 to one-half of the maximum force command if the u2 calculated in step (e) is greater than one-half of the maximum force command;
• and
• (g) determining the control force command by adding u1 and u2.

A device for moving an item, comprising:

• actuator means for applying a force to move the item;
• flexural transmission means for transmitting the force from the actuator means to the item;
• item sensor means for measuring the position of the item;
• actuator sensor means for measuring the position of the actuator means;
• and
• control means for receiving data from the item sensor means and the actuator sensor means and for controlling the actuator means such that the item is moved quickly and accurately to a desired position,
• wherein the actuator means has a desired position corresponding to the desired position of the item, and wherein the control means controls the actuator means by generating signals, referred to as control force commands, indicating how much force is to be applied by the actuator means, the signal corresponding to the largest force that the actuator means is capable of applying being called a maximum force command, and calculates each control force command by repeating the following steps using variables x1, x2, x1desired, x2desired, u1, u1old1, u1old2, u2, u2old1, u2old2, e1, e1old1, e1old2, e2, e2old1, e2old2, a11, a12, a13, a14, a15, a21, a22, a23, a24 and a25, in a series of iterations, including a first iteration and subsequent iterations, each subsequent iteration having a previous iteration, until the item and the actuator means reach their desired positions:
• (a) determining e1 by subtracting x1, which represents the current position of the item, from x1desired, which represents the desired position of the item;
• (b) determining e2 by subtracting x2, which represents the current position of the actuator means, from x2desired, which represents the desired position of the actuator means;
• (c) determining u1 by finding the sum of the products:
• (a11*e1), (a12*e1old1), (a13*e1old2), (a14*u1old1), and (a15*u1old2), wherein a11, a12, a13, a14 and a15 are coefficients for a recursive digital control algorithm, and wherein e1old2 equals zero for the first iteration and e1old1 of the previous iteration for subsequent iterations, e1old1 equals zero for the first iteration and e1 of the previous iteration for subsequent iterations, u1old2 equals zero for the first iteration and u1old1 of the previous iteration for subsequent iterations, and u1old1 equals zero for the first iteration and u1 of the previous iteration for subsequent iterations;
• (d) reducing u1 to one-half of the maximum force command if the u1 calculated in step (c) is greater than one-half of the maximum force command;
• (e) determining u2 by fining the sum of the products:
• (a21*e2), (a22*e2old1), (a23*e2old2) (a24*u2old1), and a (25*u2old2), wherein a21, a22, a23, a24 and a25 are coefficients for a recursive digital control algorithm, and wherein e2old2 equals zero for the first iteration and e2old1 of the previous iteration for subsequent iterations, e2old1 equals zero for the first iteration and e2 of the previous iteration for subsequent iterations, u2old2 equals zero for the first iteration and u2old1 of the previous iteration for subsequent iterations, and u2old1 equals zero for the first iteration and u2 of the previous iteration for subsequent iteration;
• (f) reducing u2 to one-half of the maximum force command if the u2 calculated in step (e) is greater than one-half of the maximum force command;
• and
• (g) determining the control force command by adding u1 and u2.

A system for controlling the movement of an item to a desired position by an actuator that applies force to the item through a flexural transmission, the system comprising:

• item sensor means for measuring the position of the item and generating item position data;
• actuator sensor means for measuring the position of the actuator and generating actuator position data;
• and
• control means for receiving item position data from the item sensor means and actuator position data from the actuator sensor means and for controlling the actuator such that the actuator means applies a force the strength of which is a function of the item position data, the actuator position data and the desired position.

A device for moving an item to a desired position, comprising:

• actuator means for applying a force to move the item;
• flexural transmission means for transmitting the force from the actuator means to the item;
• item sensor means for measuring the position of the item and generating item position data;
• actuator sensor means for measuring the position of the actuator means and generating actuator position data;
• and
• control means for receiving item position data from the item sensor means and actuator position data from the actuator sensor means and for controlling the actuator means such that the actuator means applies a force the strength of which is a function of the item position data, the actuator position data and the desired position.

A device for supporting and moving an item, comprising:

• carriage means for holding an item;
• a wire attached to the carriage means at first and second points such that the wire is substantially straight and is taut enough to prevent backlash, but is loose enough to absorb a substantial portion of lateral forces on the carriage means;
• actuator means for applying a force to the wire at a third point between the first and second points such that the carriage means moves in a direction substantially parallel to the wire;
• sensing means for measuring the position of the carriage means;
• and
• control means for receiving data from the sensing means and for controlling the actuator means.

A device for accurately and efficiently controlling the movement of an item by an actuator that applies force to the item through a flexural transmission, the system comprising:

• item sensor means for measuring the position of the item;
• actuator sensor means for measuring the position of the actuator;
• and
• control means for receiving data from the item sensor means and the actuator sensor means and for controlling the actuator such that the item is moved quickly and accurately to a desired position,
• wherein the actuator means has a desired position corresponding to the desired position of the item, and wherein the control means controls the actuator means by generating signals, referred to as control force commands, indicating how much force is to be applied by the actuator means, the signal corresponding to the largest force that the actuator means is capable of applying being called a maximum force command, and calculates each control force command by repeating the following steps using variables x1, x2, x1desired, x2desired, u1, u1old1, u1old2, u2, u2old1, u2old2, e1, e1old1, e1old2, e2, e2old1, e2old2, a11, a12, a13, a14, a15, a21, a22, a23, a24 and a25, in a series of iterations, including a first iteration and subsequent iterations, each subsequent iteration having a previous iteration, until the item and the actuator means reach their desired positions:
• (a) determining e1 by subtracting x1, which represents the current position of the item, from x1desired, which represents the desired position of the item;
• (b) determining e2 by subtracting x2, which represents the current position of the actuator mans, from x2desired, which represents the desired position of the actuator means;
• (c) determining u1 by finding the sum of the products:
• (a11*e1), (a12*e1old1), (a13*e1old2), (a14*u1old1), and (a15*u1old2), wherein a11, a12, a13, a14 and a15 are coefficients for a recursive digital control algorithm, and wherein e1old2 equals zero for the first iteration and e1old1 of the previous iteration for subsequent iterations, e1old1 equals zero for the first iteration and e1 of the previous iteration for subsequent iterations, u1old2 equals zero for the first iteration and u1old1 of the previous iteration for subsequent iterations, and u1old1 equals zero for the first iteration and u1 of the previous iteration for subsequent iterations;
• (d) reducing u1 to one-half of the maximum force command if the u1 calculated in step (c) is greater than one-half of the maximum force command;
• (e) determining u2 by finding the sum of the products:
• (a21*e2), (a22*e2old1), (a22*e2old2) (a24*u2old1), and a (25*u2old2), wherein a21, a22, a23, a24 and a25 are coefficients for a recursive digital control algorithm, and wherein e2old2 equals zero for the first iteration and e2old1 of the previous iteration for subsequent iterations, e2old1 equals zero for the first iteration and e2 of the previous iteration for subsequent iterations, u2old2 equals zero for the first iteration and u2old1 of the previous iteration for subsequent iterations, and u2old1 equals zero for the first iteration and u2 of the previous iteration for subsequent iteration;
• (f) reducing u2 to one-half of the maximum force command if the u2 calculated in step (e) is greater than one-half of the maximum force command;
• and
• (g) determining the control force command by adding u1 and u2.

A method for moving an item to a desired position, comprising:

• applying a force of variable strength to move the item by means of an actuator;
• transmitting the force from the actuator to the item by means of a flexural coupler;
• measuring the position of the item and generating item position data;
• measuring the position of the actuator means and generating actuator position data;
• and
• controlling the actuator such that the strength of the force is a function of the item position data, the actuator position data and the desired position of the item.